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electrical:12v:alt_and_solar [2023/07/31 14:05]
frater_secessus 		electrical:12v:alt_and_solar [2025/01/07 12:10] (current)
frater_secessus [how alternator charging helps]
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-[[lifestyle:words_of_wisdom|Words of wisdom]]: "Bulk charging requires //current//. Absorption requires //relatively high voltage// and //time at that voltage//." - secessus+> Solar and DC-DC alternator charging are going to be the best practices for maintaining charge in one's battery bank. It only requires a little math, a little discipline to stick with the math, and the right expectations about solar intake.  -- CMDR_Schrodinger((https://www.reddit.com/r/vandwellers/comments/15z8eh6/energy_management_during_trips/jxfv03f/)) 
 + 
  
 ====== Augmented solar charging ====== ====== Augmented solar charging ======
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 Alternator charging is extremely powerful and cheap compared to typical solar installs.  It works best when solar works worst:  when the batteries are deeply discharged in the morning.  The sun is weak then but the bank needs a large supply of current (early [[electrical:12v:charging#bulk_stage|Bulk charging]]).   Alternator charging is extremely powerful and cheap compared to typical solar installs.  It works best when solar works worst:  when the batteries are deeply discharged in the morning.  The sun is weak then but the bank needs a large supply of current (early [[electrical:12v:charging#bulk_stage|Bulk charging]]).  
  
-[[electrical:solar:charge_controller#pwm|PWM]] controllers are especially hamstrung in this scenario;  since they run the panels at battery voltage (Vbatt) they produce the least power exactly when the most power is required.  By the time alternator voltage (Valt) is reached PWM controllers are able to produce meaningful power.+[[electrical:solar:charge_controller#pwm|PWM]] controllers are [[electrical:solar:pwm_tweaking#pwm_s_achilles_heel|somewhat hamstrung in this scenario]];  because they run the panels ~at battery voltage((for the purposes of this discussion)) (Vbatt) they produce the least power exactly when the most power is required.  Pushing up bank voltage with the alt helps the PWM make more power.  
  
 Alt charging shovels current into the bank until Valt is reached, at which point it begins to taper off.  Solar can take it from there.  A good metaphor might be a two-stage rocket:  the alternator does the heavy lift getting the rocket off the ground then the solar charging takes care of the high altitude, high speed duties.  Alt charging shovels current into the bank until Valt is reached, at which point it begins to taper off.  Solar can take it from there.  A good metaphor might be a two-stage rocket:  the alternator does the heavy lift getting the rocket off the ground then the solar charging takes care of the high altitude, high speed duties. 
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 > Use a generator or alternator to get to 85% SOC or so early in the AM, then let Solar spend all day polishing off the last 15% because that takes time more than amps. - a64pilot((https://www.cruisersforum.com/forums/f14/time-it-takes-to-fully-charge-batteries-238875-9.html#post3223983)) > Use a generator or alternator to get to 85% SOC or so early in the AM, then let Solar spend all day polishing off the last 15% because that takes time more than amps. - a64pilot((https://www.cruisersforum.com/forums/f14/time-it-takes-to-fully-charge-batteries-238875-9.html#post3223983))
  
 +
 +The alternator can help meet [[electrical:12v:charging#charging_current|lead bank minimum charging current requirements]].  
 ===== optimal alternator contribution ===== ===== optimal alternator contribution =====
  
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   - the Li voltage curve is very flat in the middle, so the voltage delta will be stable through the "middle 80%"   - the Li voltage curve is very flat in the middle, so the voltage delta will be stable through the "middle 80%"
-  - for average users, Li will not have an Absorption stage in the lead-chemistry sense.((advanced users may find [[electrical:12v:electrical:12v:drop-in_lifepo4#mythlithium_doesn_t_need_absorption|exceptions]] to this general statement))+  - for average users, Li will not have an Absorption stage in the lead-chemistry sense.((advanced users may find [[electrical:12v:drop-in_lifepo4#mythlithium_doesn_t_need_absorption|exceptions]] to this general statement))
   - Lithium is often charged with DC-DC, which charges at the ~same voltage as solar   - Lithium is often charged with DC-DC, which charges at the ~same voltage as solar
  
electrical/12v/alt_and_solar.1690826738.txt.gz · Last modified: 2023/07/31 14:05 by frater_secessus

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